Feed water regulating apparatus for boilers



Nov. 26; 1946. I w. L. HUNTER 2,411,728

FEED WATER REGULATING APPARATUS FOR BOILERS I Filed Aug. 29, i944 2Sheets-Sheet l INVENTOR. WILL/AN L. HUN TER W, 11 my ATTORNEY Nov. 26,1946. w. HUNTER 2,411,723

FEED WATER REGULATING APPARATUS FOR BOILERS Filed Aug. 29, 1944 2Sheets-Sheet 2 IN VEN TOR. WILL/HM L HUN TER B i0. flTTOR/VEY PatentedNov. 26, 1946 6 UNITED STATE FEED WATER REGULATING APPARATUS FOR BOILERSWilliam L. Hunter, Erie, Pa., assignor to Northern Equipment Company,Erie, Pa., a corporation of Pennsylvania Application August a, 1944,Serial No. 551,694

9 Claims. (01. 122-4512.)

This invention relates to feed water regulating apparatus for boilers,and more particularly to apparatus of this type which has distinctadvantages When employed on marine boilers although 7 not limited tosuch use.

The present application is a, continuation in part of the subject matterof United States Letters Patent 2,365,081, issued to me December 12,1944.

As is well understood, it is desirable to automatically regulate thefeed water supply to boilers and maintain the boiler water level Withinpre-determined limits. This has commonly been effected in stationaryboilers by having a tube or the like in communication with the steam andwater space of the boiler whereby the water level in the tube willcorrespond to the water level in the boiler and regulate the feed waterValve in accordance with tube water level. "However, such apparatusisnot satisfactory for marineboilers since the tube water level ismaterially disturbed by the roll of the. ship resulting in rapid andhighly undesirable fluctuations in the amount of feed Water being fed tothe boiler.

I am aware that it has previously been pro-,

posed to compensate for ship roll by employing two tubes cr-the likefixed to each side of the boiler and laterally outward thereof wherebyas the boiler is tilted due to ship roll a drop in water level in onetube will be accompanied by a corresponding rise in the other tube. Bothtubesare shaped tubeis mounted externally of the drum adapted toinfluence the feed water supply so extended beyond the tubelimits thatthecontrol of the feed Water will beerratic.

-It is a primary object of my invention to provide improved feed waterregulating apparatus for boilers. V

Another object of my invention is to provide feed water regulatingapparatus for boilers and which is particularly adapted to marineboilers whereby an-accurate control of the feed water'i will bemaintained responsive to the steam detype wherein the feed water valveis actuated responsive to boiler water level variations 'or' is actuatedboth in response to water level variations andsteam flow variations inthe .system.

Another objectof my invention is to provide improved feed waterregulating apparatus for boilers which can be easily installed on aconventional boiler and which is readily adjustable.

Other objects of the invention will be increasingly apparent from a.consideration of the following description and drawings,

According to the invention, a generally V head of a boiler with the apexof the tube being disposed substantially in alignment with the verticalcenter line of the drum head and the tube arms extending atsubstantially equal angles at each side of the center line. The apex ofthe tube and the arm ends are connected to the water and steam spaces ofthe boiler whereby in a stationary boiler the water level in the'tu-bearms will correspond to boiler'water level. Each tube arm is encased bya tube' sealed atthe top and-bottom with the arm'for-ming chamberssurrounding the arms within which a volatile fluid is disposed. A

connection extends from the encasing tubes to a fluid pressure motoractuating-"the feed water valve. The fluid will volatilize in accordancewith the relative amount'of steam and water in the tube arms or boilerwater level and correspondingly operate the fluid pressure motor andfeed water valve.

When-the above described apparatus is employed on a marine boiler thewater level in one arm will drop and will rise in the other arm as theboiler is tilted but the composite level will not materially change oreffect the position of the feed water valve. Due to the normal water'levelin each arm being only a short distance lattively small distancesdespite considerable an- I 'gular .roll of the ship and well within thetube limits sothat an accurate control ofthe feed water is maintained.

In a modified form of the] apparatus a. second i fluid pressure motor isprovided which is remands despite considerable angular roll 'of theAnother object of my invention is to provide .feed "water "regulatingapparatus "ofthe above :sponsive to steam flow variations in the system=60 and the feed water valve is controlled under. the joint influence ofboiler water level variations and steam flow variations,

Infthe following description and drawings: i Fig. -"1 is 1 an endelevational view of a boiler drum and "my improved regulating apparatuswherein a single pressure motor controls actuation of the feed watervalve.

Fig. 2 is an end elevational view, largely diagrammatic, of amodification of my invention wherein two pressure motors jointly controloperation of the feed water valve.

Fig. 3 is a view generally similar to Fig. 2 showing a furthermodification of my invention, and

Fig. 4 is a vertical section through the upstanding pressure motor ofFig. 3.

Referring now to the drawings, and particularly Fig. 1, I have indicatedat IU one end portion or drum head of a conventional boiler. The normalboiler water level is indicated by the line H. A generally V shaped tube12 is disposed with its apex substantially in longitudinal alignmentwith the vertical center line of the drum head and its arms extending atsubstantially equal angles on each side of the vertical center line. Apipe 13 connects the tube apex with a three way fitting I4,

the fitting communicating with the water space of the boiler through apipe (not shown) and with a similar upper fitting l through a levelindicator tube It. The arm ends are connected by pipes l1 and It withthe fitting l5 which communicates with steam space of the boiler througha pipe (not shown). It will now be understood that the tube [2 is incommunication at the apex and arm ends with the water and steam spacesof the boiler. Valves l9 control the flow of steam and Water to the tubeand in a stationary boiler the water level in each arm of the tube willbe the same and correspond to boiler water level,

Each arm of tube I2 is surrounded by a spaced generator tube 28preferably provided with fins 2|, the tubes being sealed at the top andbottom with the arms thereby providing an encasing chamber 22 for eacharm. Disposed within'the chambers 22 is a suitable volatile fluid whichbeing in heat exchange relation with each tube arm will volatilize andcreate pressure in accord" ance with the relative amount of steam andwater in each arm. The fluid pressure is transmitted to a fluid pressuremotor generally indicated at 2 3 through a pipe 24 communicating witheach chamber 22 through a Y connection 2% at the lower end of thechambers. The fluid pressure motor actuates a valve controlling flow offeed water through a supply line 21 for the boiler.

The particular typerof fluid pressure responsive valve employedconstitutes no essential part of my invention but it may comprise afluid pressure chamber formed by a dome shaped member 28 and a diaphragm29 sealed between peripheral flanges provided on member 28 and a lowermember 3|. The diaphragm is connected to a valve stem 32 which operatesthe valve piston (not shown). The diaphragm has its underside exposed toatmosphere and is balanced by a compression spring 33 adapted to beadjusted by a plate 34 movable along guide rods 36 by manipulation ofnuts 31. The valve stem is encircled by a stufling box 38 Which preventswater in the supply line from acting on the underside of the diaphragm.v

It will now be understood that pressure exerted on the liquid ingenerator tubes 23 will be transmitted to the diaphragm whereby thevalve will be operated in correspondence with fluid pressure. Undernormal operating conditions or when the boiler is stationary the liquidlevel in the arms of tube I 2 will be substantially the same andcorrespond with boiler water level and as the level fails a greateramount of steam will be con- I tained in the tube arms resulting in anincrease.

in generator fluid pressure and causing the valve to open more. In asimilar manner the valve will be moved towards closing position as theboiler water level rises.

When the boiler is tilted due to ship roll the water level in one arm oftube l2 will be lowered causing an increase in fluid pressure in itsassociated generator tube 20 and the water level in the other arm willrise causing a decrease in fluid pressure in its associated tube and thenet result is no appreciable change in fluid pressure or no appreciablechange in valve position. It will be noted that at normal water level asindicated by line H the level in each tube arm is only a relativelysmall distance laterally from the vertical center line of the drum headand that the arms will not be completely filled or emptied despiteconsiderable angular roll of the ship thereby maintaining an accuratecontrol of the feed water valve.

Although the apparatus may be supported in any convenient manner Ipreferably support it from the boiler by the pipes extending fromfittings l4 and [5 resulting in a simple installation on a conventionalboiler. Also, the position of the valve piston for a given fluidpressure may be easily altered by adjusting nuts 33.

Referring now to Fig. 2, I have shown a modiiication of my inventionwherein two generator type units are employed.

A pair of fluid pressure motors jointly operate the feed water valve andeach motor is independently operated by one of the generator units. TheV shaped generator unit 48 is similar to that described in connectionwith Fig. 1 and varying fluid pressure is transmitted through a line 41to a fluid pressure motor $2 in accordance with boiler water levelvariations. Motor t2 may comprise a pressure chamber 43 including adiaphragm forming the base of the chamber and having its undersideexposed to atmosphere. The diaphragm is connected to a rod 44 and is ad-J'ustably loaded by a spring 46 encircling the rod having its lowermostconvolution abutting the base of a frame member 41 and its upperconvolution abutting a plate 48 movable along the rod by nut 49 threadedto the rod.

Frame member 41 preferably is formed with a circular base 5!, perforatedto have rod 44 projected therethrough, and an annular top flange 52inter-connected by oppositely disposed arms The diaphragm issealedbetween flange 52 and the flange of a dome-shaped member 54-. Thepressure motor is supported by a plate 56 extending from the housing ofthe feed water valve 57. Rod 44 is pivotally connected to a lever 58which in turn is pivoted as indicated at 53 to an arm 61 extending fromframe member ill. Lever 58 operates an arm 62 which is adjustablypivoted thereto.

A second fluid pressure motor 63 is supported by plate 56 and is similarin construction to motor 42 but disposed opposite hand. Linkage similarto that provided for motor 42 operatively connects arm 64 with motor $3.A line 6% extends from the chamber of motor 63 to a manometer unitgenerally indicated at 57 and controlling fluid pressure in line 56responsive to steam flow variationsin the system.

The steam line 68 is provided with an orifice 69 and a generally Ushaped tube ll including a reservoir 12 is connected to the steam lineacross the orifice. It is understood that the orifice is merelyillustrative of any means causing pressure dlflferential during flow inthe steam line.

Atube 13 encases a portion of tube H and is sealed thereto whereby avolatile liquid in tube 13 will create fluid pressure therein inaccordance with the relative amount of steam and water in the portion oftube 11 in heat exchange relation with the fluid in tube I3. At no flowthe water level in both legs of U tube H is the same and corresponds tothe elevation of the reservoir overflow line. As steam flows through theorifice a pressure differential is created in the right hand'or'upstream leg of U tube H and steam entering this leg causesevaporation of a portion of the fluid in tube 13 resulting in increasedpressure transmitted to the diaphragm of motor 63.

Reservoir I2 acts primarily as a capacity tank whereby at maximum loadthe liquid level in the right leg of tube II approaches the bottom ofthe leg and if the load is suddenly reduced the reservoir has sulficientcapacity to fill the right leg of the manometer with but small lossoflevel in the left leg. If the capacity tank were not provided or thesystem had a uniform cross-sectional area upon a sudden decrease in loadthe liquid level would even up in each leg but liquid would not fill theright leg and bring the regulator to the no load position.

Arms 62 and 64 are adjustably and pivotally connected to a lever I' lwhich in turn is pivotally connected to the valve stem 16. Movement ofthe valve stem in a generally vertical direction will increase ordecrease the flow of feed water to the boiler through the feed waterline11. The operation of the apparatus illustrated in Fig. 2 will now bedescribed. Upon a decrease in' boiler water level the motor 42 throughthe link means described will force valve stem 16 downwardly to causethe feed water valve to open more. In a similar manner motor 53 will beoperated upon an increase in steam flow to move the valve in openingdirection. Thus, the boiler water level and steam flow control systemsfor the feed water valve act independently and each produces the properworking pressure without reacting in any way upon the other.

Referring now to Fig. 3,1 have shown an arrangement similar tothat'illus'trated in Fig. '2 in that two fluid pressure motor-s operatethe feed water valve through link means but pressure differential in thesteam line is transmitted directly to a motor. i

Generator l8 transmits pressure through line 19 to fluid pressure motoriii in accordance with boiler water level variations as described inconnection with Fig. 2. This pressure acts'on a diaphragm 82, loaded bya spring-89 bearing against and adjustable by a nut 84 threaded to rod86 which has a headed end engaging the diaphragm. The diaphragm issealed between a dome-shaped member a and an annular flange of a'member88 having oppositely spaced arms inter-connecting the flange and a basethrough which the rod 86 is projected. For illustration, the member 87and the flange of member 88 have been shownin section. The motor issupported in any suitable manner as by being bolted toa plate extendingfrom the feed water valve housing 89.

A second fluid pressure motor generally indicated at 9| is supported bythevalve housing 89. As best illustrated in Fig. 4, the motor casing isdivided by a diaphragm 92 into an upper sealed chamber 93 and a lowersealed chamber 94. The

upper chamber is formed by a dome-shaped memcated at 98. Rotatablymounted in the lower chamber is a shaft 99 which has "the near endextended through the chamber wall and fixed to an arm IOI disposedexternally of the casing (Fig.

3). 'Also fixed to shaft 99 and disposed withinthe lower chamber is anarm I02 having its other end .pivotally connected to a headed stem I83engaging the under side of the diaphragm. The upper chamber 93communicates by a pipe I04 with the downstream or low pressure side ofan orifice L86 in the steam line I81. The lower chamber '94 communicateswith the upstream or high pressure side of the orifice through a pipeI98. The shaft 99 is suitably sealed with the casing wall.

A second shaft I09 is rotatably mounted in the lower part the motorcasing with its new end extended through the casing wall and fixed to anarm Ill disposed externally ofthe casing. An arm I I2 within the casingisfixed to shaft I99 and is pivotally fixed to the stem I I3 of thevalve whereby as the shaft is rotated the valve piston will be raised orlowered to control the flow of feed water to the :boiler through thesupply line I I4.

Rod 86 of motor BI is pivotally connected to a lever H6 which in turn isconnected to arm IIlI by a link Ill and to arm III by a link II8. Thelinks are pivotally connected to the lever and .armsby pins and areadjustable by disposing the pins indifferent holes spaced along thelever and arms.

her 96 against which one end convolution of a The operation of theapparatus Will'be described. As the boiler water level drops increasedpressure in line I9 acting on diaphragm 32 forces rod 86 tothe rightthereby forcing lever I I6 in a counterclockwise direction about thepivoted connection with link I I1. Lever I I6 through link III; willrotate arm 'I II and shaft I99 in a counterclock-wise direction. Therotation of shaft I89 will rock arm I! 2 .and lift the valve stem H3 tocause the feed water valve to open more. Upon a rise in boiler waterlevel the action will be reversed. 7

Upon an increase in steam flow through line Ill-I; thepressure on theunderside of diaphragm 924s relatively increased and stem 193 movesupwardly with shaft I99 and arm I02 rotating clockwise. Link Ill moveslever H6 clock-wise about the pivoted connection with rod 86 and link H8rotates ar-mmand shaft I89 clock-wise. Shaft I09 will lift arm I I2 andvalve stem I I3 upwardly to increase the flow of feed water. Upon adecrease of steam flow through line I91 the action will be reversed.

It will be noted that a reservoir H9 is inserted in both lines I89 andI8! serving as capacity tanks whereby the liquid level variation in eachline due'to movement of diaphragm 92 under pressure change caused bysudden load variation in the steam line is relatively small. Thus,.inboth the arrangement of Figs. 2 and 3,

the feed water valve is jointly controlled by twov substantially in avertical plane through the longitudinal center line of the boiler drumwith the tube arms extending at substantially equal angles at each sideof the plane. Further the V tube is of a size to lie entirely within anarea defined by the drum circumference, Also, the 'V tube ispreferablymounted so that the arms ex I? tend substantially equal distances aboveand below the normal water level in the boiler.

Although I have shown and described preferred embodiments of myinvention I'contemplate that numerous and extensive departures may bemade therefrom without departing from the spirit of my invention and thescope of the appended claims.

'The invention is hereby claimed as follows:

1. Feed water regulating apparatus for boilers comprising a boiler drum,a generally V-shaped tube having its apex disposed substantially inlongitudinal alignment with the vertical center line of the drum headand its arms inclined at substantially equal angles thereto, connectionsextending from the tube apex and arm ends to the steam and water spacesof the boiler whereby the water level in each arm will be the same withthe boiler in normal position, a feed water valve, a fluid pressuremotor for operating the valve, and a closed fluid pressure systemcommunicating with the motor including a volatile liquid in heatexchange relation with each arm whereby the fluid pressur will bedetermined by the composite water level in both arms and will berelatively unaffected by tilting of the boiler.

2. Feed water regulating apparatus for boilers comprising a boiler drum,a generally V shaped tube having its apex disposed substantially inlongitudinal alignment with the vertical center line of the drum headand its arms extending at substantially equal angles thereto,connections extending from the tube apex and arm ends to the steam andwater spaces; of the boiler whereby the water level in each arm will bethe same with the boiler in normal position, a feed water valve, a fluidpressure motor for operating the valve, a fluid pressure generatorcomprising a pair of tubes each sealed with an arm of the V tube andforming chambers containing a volatile fluid, and communicating meansextending from the chambers to the motor.

3. The regulating apparatus as described in claim 1 and wherein the tubearms are disposed to extend substantially equally above and below thenormal boiler water level, and th arms are inclined at an angle to havethe normal water level therein a relatively small distance laterally ofthe tube apex whereby the water level will remain within the limits ofeach arm despite considerable angular movement of the boiler.

i. Feed water regulating apparatus for boilers comprising a boiler drum,a generally V shaped tube mounted on a drum head of the boiler with itsapex disposed substantially in a vertical longitudinal plane through thecenter of the drum head and its arms extending at substantially equalangles on each side of said plane, connections extending from the tubeapex and arm,

ends to the steam and water spaces of the boiler whereby the water levelin each arm will bethe same with th boiler in normal position, agenerally V shaped generator unit comprising closed chambers encasingeach arm and a volatile liquid in the chambers adapted to volatilize andcreate pressure in accordance with th relative amount of steam and waterin each arm, a feed water valve, a fluid pressure motor for operatingthe valve, and communicating means extending from the chambers to themotor.

5. The combination with a boiler drum, a steam line extending from theboiler drum, a feed water supply line, and a feed water valve in thesupply line, of feed water regulating apparatus comprising a generally Vshaped tube having its apex disposed substantially at the verticalcenter line of the drum and its arms extending at substantially equalangles thereto, said tube being connected to the water and steam spacesof the drum at the apex and arm ends whereby boiler water level will becommunicated to the tube arms,'a feed Watervalve, a fluid pressuremotor, a closed fluid pressure system including a-volatile liquid inheat exchange relation with th tube arms and communicating with themotor whereby the motor will be operatedin accordance with the compositewater level in both arms, a second fluid pressure motor adapted to beindependently operated in response to steam flow variations, and linkmeans operatively connecting both motors and the feed water valve.

6. The regulating apparatus as described in claim 5 and wherein the linkmeans comprises a pair of arms each pivotally mounted on a differentmotor and operable by its associated motor, a pair of links eachpivotally connected to a different arm, a lever pivotally connected toboth said links, and the lever being pivotally connected to the stem ofthe feed water valve whereby the lever may pivot about either linkconnection to operat the valve.

7. The regulating apparatus as described in claim 5 and wherein thesteam line is provided with means creating pressure differential duringflow, a connection across said means comprising a generally U form tubeand a reservoir, a generator tube forming a chamber encasing theupstream leg of the U tube and containing a volatile liquid adapted tocreate varying pressure in accordance with the relative amount of steamand water in said upstream leg, and communicating means extending fromsaid generator tube to on of the pressure motors.

8. The regulating apparatus as described in claim 5 and wherein thesecond fluid pressure motor comprises a pair of scaled chambers dividedby a diaphragm, means in the steam line creating pressure differentialduring flow, a conduit connecting one of said chambers with the steamline upstream of said means, a second conduit connecting the otherchamber with the steam line downstream of said means, and the diaphragmbeing operatively connected to the link means.

9. Feed water regulating apparatus for boilers comprising a boiler drum,a pair of upwardly extending arms mounted on one drum head of the boilerand lying within a periphery defined by the drum head, the upper ends ofthe arms being substantially equally spaced at opposite sides of avertical plane bi-secting the drum and connected to the steam space ofthe boiler, the lower ends of the arms being substantially equallyspaced at opposite sides of said vertical plane bisecting the drum andconnected to the water space of the boiler, a feed water valve, a fluidpressure motor for operating the valve, a closed fluid pressure systemcommunicating with the motor including a volatile liquid in heat exchangrelation with each arm whereby the fluid pressure will be determined bythe composite water level in both arms and will be relatively unaffectedby tilting of the boiler, a second fluid pressure motor adapted to beindependently operated in response to steam flow variations, and linkmeans operatively connecting both motors and the feed water valve.

WILLIAM L. HUNTER.

